All scam sites lack captcha, just as observation.
Captcha is to protect from DoS, I think. That is also a problem for API, isnt it?
I think API is (or will get) a nightmare.
Adding captchas to any website is trivial thing and if I remember correctly I saw several scam services that used them in past, so this won't protect you from anything.
I would suggest everyone to report this phishing website that first started to clone new Chipmixer homepage.
It's interesting to see that they even copied tor link that they changed domain from .onion to .onl that works in clearnet

